Emphysema is an abnormal and irreversible enlargement of the air spaces around the bronchioles caused by chronic inflammation. It is also characterized by the destruction of the alveolar walls of the lungs. As the damage to the alveolar walls increases the lungs lose their elasticity. The progressive symptoms include shortness of breath upon minimal exertion, frequent respiratory infections and chronic cough. Emphysema is considered to be one of the chronic pulmonary diseases.
The hydrolytic action of the enzyme human leukocyte elastase (HLE) on the connective tissue component elastin is believed to be the cause of pulmonary emphysema. Like other serine proteases, elastase may be inactivated by inhibitors which block the active site of the enzyme by binding tightly thereto. Under normal conditions, these enzymes are prevented from causing damage by the action of the natural inhibitor .alpha..sub.1 -antitrypsin, which is a glycoprotein present in human serum.
It would appear that the inflammation caused by cigarette smoke provokes the release of a large amount of leukocyte elastase and hence an imbalance between the two enzymes results. The quantity of .alpha..sub.1 -antitrypsin present is thus insufficient to inhibit enough of the leukocyte elastase. Consequently the excess elastase begins adhering to the surfaces of elastin fibers in the lungs. This eventually leads to the lung damage characteristic of emphysema.
Additionally, it is believed that the action of cigarette smoke functions to inactivate the .alpha..sub.1 -antitrypsin. Also an .alpha..sub.1 -antitrypsin deficiency may be caused by hereditary factors.
Cephalosporin drugs are widely used for the treatment and prevention of various infectious diseases caused by pathogenic bacteria.
U.S. Pat. No. 4,547,371, discloses that certain substituted cephalosporin sulfones demonstrate potent elastase inhibitory effects. U.S. Pat. No. 4,711,886, describes .beta.-lactam derivatives which are found to be potent elastase inhibitors. U.K. Patent Application GB 2,198,640A, relates to penicillin derivatives useful as anti-inflammatory and anti-degenerative agents. An article in Nature Vol. 322, Jul. 10, 1886, by J. B. Doherty et al. illustrates that cephalosporin antibiotics can be modified to inhibit human leukocyte elastase. Additionally, a study of 1,3-dipolar cycloaddition reactions of cephalosporin derivatives is provided in a paper entitled, "Cycloaddition Reactions of Cephalosporin Compounds XI" by J. Pitlik et al, J. Heterocyclic Chem., 26. 461(1989).